The use of highly paraffinic kerosene and gas oil hydrocarbon fuel fractions in fuel compositions for domestic heating, lighting and cooking permits exceptionally low NOx and soot emissions.
Highly paraffinic hydrocarbon products that are boiling in the kerosene and gasoil range may conveniently be derived from the products of a Fischer-Tropsch process, such as the low temperature Fischer-Tropsch process disclosed in EP-A-1523538 and EP-A-1523539, or from mineral oil derived sources, e.g. slack waxes. Other processes delivering such products include a process for the reductive decarboxylation/decarbonylation reaction of fatty acids and/or fatty acid esters as for instance disclosed in WO-A-2004022674 and WO-A-2006075057.
Domestic heating appliances such as evaporator burners and pressure jet burners are provided with a flame detector. These detectors act as a safety measure by monitoring the constant presence of a flame. Many of the flame detectors in service today are based on optical measurements (e.g. photo cells) and detect a signal at a particular wavelength of light, in particular the light emitted by the flame of mineral oil-derived fuels in the visible yellow and/or red light spectrum. Applicants found that highly paraffinic synthetic fuels such as Fischer-Tropsch derived fuels or natural fatty acid derived fuels as those disclosed in EP-A-1546288 result in a change of flame colour towards the visible blue spectrum, or even fall outside the visible spectrum, resulting in transparent flames. This blue or transparent colour cannot be registered correctly by the above-described detectors since the detector is unable to recognise the flame correctly, thereby leading to false shutdowns.
Applicants have now found that a domestic heating fuel composition comprising paraffinic synthetic fuels such as Fischer-Tropsch derived fuels or natural fatty acid derived fuels as disclosed in EP-A-1546288 can be formulated that permits to obtain the desired benefit in reduction in emissions, while also generating a yellow flame and enabling conventional flame sensors to detect a flame signal.
This object is achieved by the following composition: